The present invention relates generally to the field of optical systems. More particularly, the present invention relates to high performance pulsed laser sources that operate with high power, narrow spectral linewidths, and freedom to adjust pulse parameters and characteristics. Embodiments of the present invention are useful in a variety of applications including nonlinear frequency conversion laser systems, light detection and ranging (LIDAR) systems, laser-based remote sensing systems, laser-based communications systems, and the like.
Fiber lasers have advanced to become economical and efficient high power infrared laser sources. Average optical output powers of tens of kilowatts are currently available in commercial fiber laser systems. FIG. 1 is a schematic of a conventional fiber laser 100 including a master oscillator fiber amplifier (MOFA) architecture. The master oscillator 110 (also known as the seed laser) emits a low power optical signal that is coupled into the amplifier section 130 through an optical isolator 120. The optical isolator protects the master oscillator from any light counter propagating back through the amplifier section. The amplifier section consists of a length of gain fiber that is pumped by one or more pump lasers 140 (typically diode lasers) through a pump coupler 150. The gain fiber may be multi or single spatial mode, polarization random or maintaining, cladding pumped or core pumped, and may have a variety of dopants (for example Yb, Er, Nd, Pr, etc.) depending on the emission and pumping wavelengths. The pump laser light is absorbed by the dopants in the gain fiber, raising the dopants into an excited state. The emission from the master oscillator is amplified through stimulated emission as it interacts with the excited dopants implanted in the fiber core.
Although high power, continuous wave fiber lasers have found use in some applications, there is a need in the art for improved pulsed fiber laser systems.